Eur. Phys. J. D 32, 69-73 (2005)
https://doi.org/10.1140/epjd/e2004-00186-y

Threshold of molecular bound state and BCS transition in dense ultracold Fermi gases with Feshbach resonance

Laboratoire de Physique Statistique, École Normale Supérieure (Laboratoire associé au Centre National de la Recherche Scientifique et aux universités Paris-6 et Paris-7.) , 24 rue Lhomond, 75231 Paris Cedex 05, France

Corresponding author: ^a combesco@lps.ens.fr

Received: 26 March 2004
Published online: 14 December 2004

Abstract

We consider the normal state of a dense ultracold atomic Fermi gas in the presence of a Feshbach resonance. We study the BCS and the molecular instabilities and their interplay, within the framework of a recent many-body approach. We find surprisingly that, in the temperature domain where the BCS phase is present, there is a non zero lower bound for the binding energy of molecules at rest. This could give an experimental mean to show the existence of the BCS phase without observing it directly.